Preheater for fluid-fuel furnaces.



I P.A`.JA00BS. f PRBHEATEB. FOR `TLUID FUEL FURNAGES.

APPLLQMION 111215" nu 4, 1914.

Patented 119119,1915.

FRANCIS A. JACOBS, OF MONTREAL, QUEBEC, CANADA.

P'REHEATER FOR AFLUID-'FUEL 'UBNAGES.

Specification of Letters Patient.

Patented Feb. 9, 1915.

Applicationzled Masy 4, 19.14. Serial No. 836,363.

T0 all whom it may concern:

Be it known that I, FRANCIS A. JAGoBs, a citizen of the Dominion ofCanada, and resident of the city of Montreal, in the Province of Quebecand Dominion of Canada, have invented certain `new and useifsulImprovements in Preheaters for Fluid-Fuel Furnaces, and do herebydeclare that the following is a full, clear, and eXact description ofsame.

This invention relates to improvements in preheating apparatus for usein connection with oil or gas furnaces and the like, and the object isto provide means for preheating both the air and gas delivered to theburners using as the heating agent waste heat from the furnace.

A further object is to provide a preheater of simple and durableconstruction, compact in design, and having a large amount of heatingsurface so disposed as to prolong the passage of the fluids over theheating surface.

The device consists essentially of an annular chamber for each fluid tobe heated, said chamber being substantially helical in form. Thesechambers surround la stack through which gases escape from the furnace.The chambers are separate and are individually connected to the burner.

In the drawings-which illustrate the invention 'Figure 1 is a plan Viewof the device. Fig. 2 is a side elevation. Fig. 3 is a verticalsectional View through the center of the preheating apparatus.

Referring more particularly to the drawings, 5A designates afurnaceheated by one or more gas or oil burners 6, and having a stack 7 for theescape of waste gases communicating at its lower end with the furnacethrough a passage 9.

The preheating apparatus is arranged in the stack, and consists of aseparate heater for each fluid to be dealt with, for the reason that inmany instances these fluids are heated to the point of incandescence, sothat` if mingled, combustion would be set up spontaneously. I

In the drawing, an apparatus is shown adapted for heating air and oil orother gas, but it is obvious that in other types of furnace whereadditional gases are used, ad ditional heaters may be'provided asrerequired. Each heater consists of a tube having inner and outerhelical corrugated walls lO and 11 respectively, spaced apart so as toform an annular chamber 12 of such form that fluid flowing therethroughwill traverse a substantially helical path. With- 1n the inner wall 10is a passage 13 for the heating agent. The chambers 12 are com- -pletely`closed at the ends by Walls 14, 14

so that the heating agent cannot enter the annular chamber and minglewith the fluid therein. In designing such preheating apparatus, the sizeof the heating chambers will be regulated according to the volume offluid-to be handled, thus in Fig. 3, a com paratively `small heater 15is shown for gas and a large heater 16 forvair. In this form, the airheater is placed in the hottest part, in order to heat a large volume ofair in a heater of minimum size. The air chamber is provided at the topwith an inlet 17 and at the bottom with an outlet 18 and the oil chamberis provided with a similar inlet 17 and outlet 18', so that the fluid tobe .heated passes through the heaters in the opposite direction, to theheating agent. In

the installation illustrated, the gas heater 15 is connected to theburner by a pipe 19, and the air heater by a pipe 20, entirely separatedfrom each other, so that the two fluids do not mingle before reachingthe combustion point ,in the burner.

From the foregoing description, it will be seen that means are providedto utilize the waste heat of a furnace for preheating the fuel, so thata greater efficiency is obtained in the furnace. The preheater is simpleand durable in design, inexpensive to maintain, and eiiicientinoperation, as it reclaims waste heat. The use of helical corrugatedwalls not only increases the heating surface, but compels the fluidheated to remaink longer in contact with the heating surfaces.

Another great advantage resides in the use of these corrugated walls,which is that eX- pansion and contiaction of the heaters are taken up inthe walls themselves, so that there is practically no change in theoverall length, and pipe connections are not unduly stressed.

Having thus described my invention, what I claim is 1. The combinationwith a stack of an oil burning furnace of a plurality of independentheating units within the stack for Separately heating oil and air to auniform temperature, each unit formed of a double llO walled tubularbody having spaces between the walls thereof closed at the ends to forman annular chamber surroundingthe bore of the body, an inlet and anoutlet foreach said chamber, a burner and conduits communicating withsaid burner and heating units for conductin the heated oil and airseparately to said urner.

2. A device of the character described, comprising the combination witha stack or other passage for the escape of Waste heat,

of a plurality of tubular members arranged axially in line Within saidpassage, each of said members having inner and outer helical corrugatedWalls connected together at the S. R. W. ALLEN, G. M. MORELAND.

